A Subaru/HDS study of Lead (Pb) abundances in eight s-process-element-rich, metal-poor stars

Abstract

We report the abundances of neutron-capture elements in eight carbon-rich, metal-poor (-2.7=<[Fe/H]=<-1.9) stars observed with the Subaru Telescope High Dispersion Spectrograph. The derived abundance patterns indicate that the neutron-capture elements in these objects primarily originated from s-process nucleosynthesis, although the [Ba/Eu] abundance ratios in some objects are lower than that of the solar-system s-process component. The present analysis has yielded the Pb abundances for seven objects, as well as an upper limit for one object, from use of the Pb I 4057A and 3683A lines. The values of [Pb/Ba] in these objects cover a wide range, between -0.3 and +1.2. Theoretical studies of s-process nucleosynthesis at low metallicity are required to explain this large dispersion of the [Pb/Ba] values. Variations in radial velocity have been found for two of the eight objects, suggesting that, at least in these instances, the observed excess of s-process elements is due to the transfer of material across a binary system including an AGB star. Comparisons with predictions of AGB nucleosynthesis models are discussed.

23 pages, 3 figures, ApJ, in press

Cited by in corpus (127)

• The s Process: Nuclear Physics, Stellar Models, Observations
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• The Stellar Abundances for Galactic Archeology (SAGA) Database - Compilation of the Characteristics of Known Extremely Metal-Poor Stars
• Spectroscopic Studies of Extremly Metal-Poor Stars with Subaru/HDS:II.The r-process Elements, Including Thorium
• The Binary Frequency Among Carbon-Enhanced, s-Process Rich, Metal-Poor Stars
• Galactic Chemical Evolution and solar s-process abundances: dependence on the 13C-pocket structure
• The s-Process in Low Metallicity Stars. II. Interpretation of High-Resolution Spectroscopic Observations with AGB models
• Near-UV Observations of HD221170: New Insights into the Nature of r-Process-Rich Stars
• Neutron-capture elements in the very metal-poor star HD122563
• HE1327-2326, an unevolved star with [Fe/H]<-5.0. I. A Comprehensive Abundance Analysis
• Is HE0107-5240 A Primordial Star? -- The Characteristics of Extremely Metal-Poor Carbon-Rich Stars --
• The intermediate neutron-capture process and carbon-enhanced metal-poor stars
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• Spectroscopic Studies of Very Metal-Poor Stars with the Subaru High Dispersion Spectrograph. III. Light Neutron-Capture Elements
• Bright Metal-Poor Stars from the Hamburg/ESO Survey. I. Selection and Follow-up Observations from 329 Fields
• The Ubiquity of the Rapid Neutron-Capture Process
• Line lists for the A2PI-X2Sigma+ (red) and {B2Sigma+-X2Sigma} (violet) Systems of CN, 13C14N, and 12C15N, and Application to Astronomical Spectra
• Iron and s-elements abundance variations in NGC5286: comparison with anomalous globular clusters and Milky Way satellites
• The role of binaries in the enrichment of the early Galactic halo. III. Carbon-enhanced metal-poor stars -- CEMP-s stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) III. HE 0338-3945 and the formation of the r+s stars
• An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars
• Dynamical Relics of the Ancient Galactic Halo
• Stellar Archaeology -- Exploring the Universe with Metal-Poor Stars
• Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample
• Abundance Analysis of HE2148-1247, A Star With Extremely Enhanced Neutron Capture Elements
• s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models
• The Origin of Carbon-Enhancement and Initial Mass Function of Extremely Metal-Poor Stars in the Galactic Halo
• The End of Nucleosynthesis: Production of Lead and Thorium in the Early Galaxy
• Carbon Stars in the Hamburg/ESO Survey: Abundances
• More lead stars
• First stars IV.CS 29497-030: Evidence for operation of the s-process at very low metallicity
• First stars X. The nature of three unevolved Carbon-Enhanced Metal-Poor stars
• Analysis of the carbon-rich very metal-poor dwarf G77-61
• CS 30322-023: an ultra metal-poor TP-AGB star?
• New analysis of the two carbon-rich stars CS 22948-27 and CS 29497-34 : binarity and neutron-capture elements
• CS22964-161: A Double-Lined Carbon- and s-Process-Enhanced Metal-Poor Binary Star
• Three carbon-enhanced metal-poor dwarf stars from the SDSS - Chemical abundances from CO^5BOLD 3D hydrodynamical model atmospheres
• Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes
• Dredge-up and envelope burning in intermediate mass giants of very low metallicity
• A Search for Nitrogen-Enhanced Metal-Poor Stars
• The R-Process Alliance: A Comprehensive Abundance Analysis of HD 222925, a Metal-Poor Star with an Extreme R-Process Enhancement of [Eu/H] = -0.14
• Elemental abundances and classification of CEMP stars
• Fluorine and Sodium in C-rich low-metallicity stars
• Neutron-Capture Nucleosynthesis in the First Stars
• Metal-Poor Stars Observed with the Magellan Telescope. III. New Extremely and Ultra Metal-Poor Stars from SDSS/SEGUE and Insights on the Formation of Ultra Metal-Poor Stars
• A high-resolution spectral analysis of three carbon-enhanced metal-poor stars
• Chemical abundances in 43 metal-poor stars
• The s-process in metal-poor stars: Abundances for 22 neutron-capture elements in CS 31062-050
• BD +44 493: A Ninth Magnitude Messenger from the Early Universe; Carbon Enhanced and Beryllium Poor
• Detailed Abundances of Two Very Metal-Poor Stars in Dwarf Galaxies
• Are There Any Stars Lacking Neutron-Capture Elements? Evidence from Strontium and Barium
• Low-mass supernovae in the early Galactic halo: source of the double r/s-process enriched halo stars?
• Progenitors of Type Ia Supernovae: Binary Stars with White Dwarf Companions
• Lithium abundances in CEMP stars
• RAVE J203843.2-002333: The first highly r-process-enhanced star identified in the RAVE survey
• Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. I. Detailed analysis of 15 binary stars with known orbital periods
• Estimation of Carbon Abundances in Metal-Poor Stars. I. Application to the "Strong G-band" stars of Beers, Preston, & Shectman
• New Neutron-Capture Site in Massive Pop III and Pop II Stars as a Source for Heavy Elements in the Early Galaxy
• Evidence for nucleosynthesis in supernova $\gamma$-process: Universal scaling on p-nuclei
• Carbon and Strontium Abundances of Metal-Poor Stars
• Observational Constraints on First-Star Nucleosynthesis. II. Spectroscopy of an Ultra Metal-Poor CEMP-no Star
• The effects of thermohaline mixing on low-metallicity asymptotic giant branch stars
• From actinides to zinc: Using the full abundance pattern of the brightest star in Reticulum II to distinguish between different r-process sites
• Rubidium and lead abundances in giant stars of the globular clusters M4 and M5
• Learning about the intermediate neutron-capture process from lead abundances
• Carbon-Enhanced Hyper-metal-poor Stars and the Stellar IMF at Low Metallicity
• Europium Isotope Ratios in s-Process-Element-Enhanced, Metal-Poor Stars: A New Probe of the 151Sm Branching
• The Hobby-Eberly Telescope "Chemical Abundances of Stars in the Halo" (CASH) Project. I. The Lithium-, s-, and r-Enhanced Metal-Poor Giant HKII 17435-00532
• Constraints of the physics of low-mass AGB stars from CH and CEMP stars
• Binary Blue Metal-Poor Stars: Evidence for AGB Mass Transfer
• Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars
• Are some CEMP-s stars the daughters of spinstars?
• Hubble Space Telescope Near-Ultraviolet Spectroscopy of the Bright CEMP-no Star BD+44 493
• Spectroscopic Studies of Extremely Metal-Poor Stars with Subaru/HDS:I. Observational Data
• Rubidium and lead abundances in giant stars of the globular clusters M 13 and NGC 6752
• Hubble Space Telescope Near-Ultraviolet Spectroscopy of Bright CEMP-s Stars
• Very metal-poor stars observed by the RAVE survey
• uvby(-$\beta$) photometry of high-velocity and metal-poor stars X. Stars of very low metal abundance: observations, reddenings, metallicities, classifications, distances, and relative ages
• Enrichment of Very Metal-Poor Stars with Both r-Process and s-Process Elements from 8-10 M_\odot Stars
• Chemical abundances and kinematics of a sample of metal-rich barium stars
• Spectroscopic study of CEMP-(s & r/s) stars- Revisiting classification criteria and formation scenarios, highlighting i-process nucleosynthesis
• Carbon-Enhanced Metal-Poor Stars. Osmium and Iridium Abundances in the Neutron-Capture-Enhanced Subgiants CS31062-050 and LP625-44
• Understanding the orbital periods of CEMP-s stars
• The CH fraction of Carbon stars at high Galactic latitudes
• Chemical enrichment mechanisms in Omega Centauri: clues from neutron-capture elements
• The 139La(n,gamma) cross section: key for the onset of the s process
• Chemical analysis of CH stars - I: atmospheric parameters and elemental abundances
• Chemical analysis of CH stars - II: atmospheric parameters and elemental abundances
• The low Sr/Ba ratio on some extremely metal-poor stars
• CD-62\degree1346: an extreme halo or hypervelocity CH~star?
• Lithium in CEMP-no stars: A new constraint on the lithium depletion mechanism in the early universe
• Abundances of Extremely Metal-Poor Star Candidates
• V453 Oph: a s-process enriched, but carbon-deficient RV Tauri star of low intrinsic metallicity
• Subaru/HDS study of CH stars: elemental abundances for stellar neutron-capture process studies
• New \textsl{s}-process Mechanism in Rapidly-Rotating Massive Pop II Stars
• Identification of a Group III CEMP-no Star in the Dwarf Spheroidal Galaxy Canes Venatici I
• AGB nucleosynthesis in the Large Magellanic Cloud. Detailed abundance analysis of the RV Tauri star MACHO47.2496.8
• Neutron-capture elements in dwarf galaxies II: Challenges for the s- and i-processes at low metallicity
• Carbon-enhanced Metal-poor Stars in SDSS/SEGUE. II. Comparison of CEMP Star Frequencies with Binary Population Synthesis Models
• Atomic and Molecular Data for Stellar Physics: Former Successes and Future Challenges
• Neutron-capture elements in the s- and r-process-rich stars: Constraints on neutron-capture nucleosynthesis processes
• Enrichment of lead (Pb) in the Galactic halo
• Interpretation of CEMP(s) and CEMP(s + r) Stars with AGB Models
• Europium s-process signature at close-to-solar metallicity in stardust SiC grains from AGB stars
• The s-process in stellar population synthesis: a new approach to understanding AGB stars
• Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS
• The origin of the lead-rich stars in Galactic halo: investigation of the model parameters for the s-process
• Carbon Abundances of Three Carbon-Enhanced Metal-Poor Stars from High-Resolution Gemini-S/bHROS Spectra of the 8727A [C I] Line
• Detection of Pb II in the Ultraviolet Spectra of Three Metal-Poor Stars
• Abundances of neutron-capture elements in G 24-25. A halo-population CH subgiant
• Detailed abundances in a sample of very metal poor stars
• Observational nuclear astrophysics: neutron-capture element abundances in old, metal-poor stars
• Spectroscopic study of four metal-poor carbon stars from the Hamburg/ESO Survey: On confirming the low-mass nature of their companions
• Chemodynamical study of two CEMP-no stars from the Hamburg/ESO Survey
• HD 209621: Abundances of neutron-capture elements
• Investigation for the enrichment pattern of the element abundances in r+s star HE 0338-3945: a special r-II star?
• The study of s-process nucleosynthesis based on barium stars, CEMP-s and CEMP-r/s stars
• Probing the nucleosynthetic contribution of low-metallicity, low-mass star companions of CEMP stars
• Optical and NIR spectroscopy of cool CEMP stars to probe the nucleosynthesis in low mass AGB binary system
• Investigation of the single neutron exposure model for the s-process: the primary nature of the neutron source
• Study of the abundance features of the metal-poor star HD 94028
• Stellar s-process neutron capture cross section of Ce isotopes
• Chemical analysis of carbon stars in the Local Group: I. The Small Magellanic Cloud and the Sagittarius dwarf spheroidal galaxy
• Ba Isotope Ratio in CEMP-s and CEMP-rs Stars as a Signature of s-Process and i-Process
• CEMP-s and CEMP-s/r stars: last update